Optical fibers are a medium through which light signals can travel. A typical optical fiber is comprised of a glass core, for example silica glass, surrounded by an encapsulating material, also typically a glass, such as phosphate glass. A light signal travels through a light transmission pathway in the core of the optical fiber. Typically, the polarization of the light signal rotates as it travels through the optical fiber. In many instances, light signals exhibit different properties depending of the polarization of the light signal. Some optical assemblies require that an incoming light signal reach the assembly having a certain polarization in order for the assembly to operate properly. These light signals often reach the optical assembles by traveling through polaization maintaining optical fibers, which are optical fibers that have the ability to propagate light signals at a controlled polarization.
Polarization maintaining optical fibers typically contain a core and two stress rods aligned with the core, approximately 180° apart from each other. The stress rods induce a stress on the fiber, forcing the light signal to travel in a controlled polarization. Some optical assemblies require two adjacent polarized light signals to reach the optical assembly in order for the assembly to work properly. In these assemblies, the two polarization maintaining optical fibers are typically housed in a single optical fiber capillary. However, in order for both light signals to have controlled polarizations, a line connecting the stress rods from one polarization maintaining optical fiber should be disposed at an angle of approximately 90° from a line connecting the stress rods from the other polarization maintaining optical fiber.
A current method for accomplishing this task includes manually feeding two polarization maintaining optical fibers into one optical fiber capillary. This task is complicated due to the small dimensions of both the polarization maintaining optical fibers and the opening in the capillary. In addition the fibers are often brittle and should one of the fibers break during an attempt to insert a fiber into the capillary opening, the process of inserting the fibers into the capillary must be restarted. Once the fibers are inserted into the capillary, the fibers are manually rotated such that a line connecting the stress rods within one fiber is approximately 90° apart from a line connecting the stress rods within the other fiber. Again due to the small dimensions of the fibers and the capillary, manual manipulation is relatively imprecise. Once the fibers are aligned to the selected 90° orientation, the fibers are manually held into position while an epoxy cures, affixing the fibers in the selected orientation within the capillary.